The present invention relates to a method of making a self-controlled heater and improved self-controlled heater.
The polymeric semiconductor compound based on lampblack and consisting essentially of about 60% by weight of low density polyethylene, of about 8.5% by weight ethylene vinyl acetate copolymer, of about 4.0% by weight of a spreading agent consisting of calcium stearate, of about 3.0% by weight of an antioxidant and about 0.5% by weight of a coupling agent consisting of calcium titanate described in the above copending application and the semiconductor body made by extruding and calendering it are useful in making a self-controlled heater. The disclosure of the above copending application should be considered as incorporated by reference in the above application.